Current sensorless field oriented control of a RSM by Extended-Kalman-Filter based state estimation

The field of sensorless control is commonly associated with encoderless control, which is the mostly investigated type of control under relinquishment of sensor technology. Nevertheless, also other types of sensorless control schemes have been introduced successfully. Control without DC-Link voltage sensors is an often used technology. The reduction of current sensors can also be realized by using only one current sensor in the DC-Link branch. Whereas the control without a single current sensor is a rarely investigated technology and objective of this paper. Current sensorless control can be used in case of current sensor faults and for the cost reduction of the drive system. In this paper, a current sensorless field oriented control for a synchronous reluctance machine with distributed windings is introduced. The necessary state estimation is realized by an Extended-Kalman- Filter. Errors due to dead time effects are compensated by a proposed compensation method. The scheme is verified by measurement results. It is shown, that the performance and the reliability of the current sensorless field oriented control is comparable to the conventional control.